Process for the preparation of 1-diorganocarbamoyl-polyalkylpiperidines

ABSTRACT

Compounds containing a group of the formula I ##STR1## in which R is H or C 1  -C 4  -alkyl, R 1  is H, CN, an acyloxy group or a free valency and R 2  and R 3  are organic radicals can be prepared in a simple manner from the corresponding compounds containing a group of the formula Ia ##STR2## by stepwise reaction with phosgene and a secondary amine R 2  --NH--R 3  in the presence of a molar amount of a base. The N-diorganocarbamoyl compounds containing the group I are outstanding light stabilizers, in particular for organic polymers. They can be converted by secondary reactions into other compounds which contain the group I and which are not accessible by direct phosgenation. Many of the products thus obtainable by phosgenation or conversion are novel compounds.

The invention relates to a process for the preparation ofpolyalkylpiperidine derivatives which are substituted in the 1-positionby a diorganocarbamoyl group, and to novel compounds from this group ofpolyalkylpiperidine derivatives.

It has been disclosed that sterically hindered polyakylpiperidinederivatives are excellent light stabilisers for organic materials, inparticular for organic polymers. It is important here that thepiperidine ring is alkylated in the 2- and 6-positions, whilst thenitrogen in the 1-position can be unsubstituted or substituted byvarious organic groups. German Offenlegungsschrift No. 2,258,752 hasaleady proposed the use of polyalkylpiperidine derivatives which have,on the nitrogen of the piperidine ring, a carbamoyl group --CO--NH₂ or amonosubstituted or disubstituted carbamoyl group --CO--NHR or --CO--NR₂,in which R is an organic radical. Those compounds containing thecarbamoyl radical --CO--NHR can be prepared from the NH-piperidines byreaction with isocyanates, and German Offenlegungsschrift No. 2,258,752has disclosed a number of specific compounds of this type. However, thisOffenlegungsschrift mentioned compounds having a disubstituted carbamoylgroup --CO--NR₂ on the piperidine nitrogen only in general terms, andrecommended reaction of the corresponding NH-piperidines with acarbamoyl chloride Cl--CO--NR₂ or with a carbamic acid ester RO--CO--NR₂as a general method of preparation. If attempts are made to use eitherof these methods for the preparation of1-diorganocarbamoyl-polyalkylpiperidines, difficulties are encountered.No reaction takes place at room temperature or slightly elevatedtemperature, and at higher temperatures dark-coloured reaction productsare obtained, from which only a low yield of the desired products areobtained by the conventional methods of purification. However, since theresulting N-disubstituted 1-carbamoylpiperidines have proved to besuperior stabilisers to the monosubstituted analogues, there was aconsiderable interest in discovering an industrially usable preparationprocess for these compounds.

Furthermore, S. S. Berg and D. F. Cowling (J. Chem. Soc. (C) 1971,1653-8) have described the reaction of 2,2,6,6-tetramethylpiperidinewith phosgene in the molar ratio of 2:1. The result was however not theformation of the desired urea but the cleavage of the piperidine ring,whereby a mixture of isomeric noncyclic isocyanates was formed.

It has been found that, surprisingly, sterically hinderedpolyalkylpiperidines which are unsubstituted in the 1-position canreadily be reacted with phosgene at only low temperatures, and that the1-chlorocarbonyl compounds thus obtained can just as readily be furtherreacted with secondary amines to give the corresponding1-diorganocarbamoyl compounds. The chlorocarbonyl compounds can bereacted with the secondary amine without being isolated, i.e. the tworeaction stages can be carried out as a one-pot reaction. Thepreparation of unsymmetrical tetra-substituted ureas from a secondaryamine A by stepwise reaction with phosgene and a secondary amine B isknown per se, and it is also known that such a reaction is carried outin an inert solvent and in the presence of a stoichiometric amount of anHCl-bonding base. However, it was not to be expected that this reactioncan be applied to the sterically hindered 2,2,6,6-tetraalkylpiperidinesunder such mild conditions, since it is known that acylation of suchpiperidines with carboxylic acid chlorides proceeds only at elevatedtemperature and even then only relatively slowly.

The invention thus relates to a process for the preparation of compoundscontaining a group of the formula I ##STR3## in which R is hydrogen orC₁ -C₄ -alkyl, R¹ is hydrogen, C₁ -C₁₂ -alkoxy, C₂ -C₂₀ -alkanoyloxy,benzoyloxy, C₃ -C₂₅ -carbamoyloxy, CN or a free valency, R² is C₁ -C₁₈-alkyl, C₃ -C₁₂ -alkoxyalkyl, C₂ -C₈ -hydroxyalkyl, C³ -C₁₂ -alkenyl C₇-C₁₄ -aralkyl, C₆ -C₁₄ -aryl, C₇ -C₁₄ -alkaryl, C_(3-C) ₇ -cycloalkyl or2,2,6,6-tetramethylpiperidin-4-yl and R³ has one of the meanings of R²,or R² and R³, together with the N atom to which they are bonded, form a5- to 7-membered heterocyclic ring, and in which the free valency(valencies) is (are) bonded to hydrogen, oxo-oxygen or any low-molecularor high-molecular organic radical, by reacting a compound containing agroup of the formula Ia ##STR4## with phosgene in an inert solvent inthe presence of a molar amount of a base, and subsequently reacting theproduct with a secondary amine of the formula R² --NH--R³, also in thepresence of a molar amount of a base.

An alkyl radical R in formula I or Ia can be, for example, methyl,ethyl, propyl or butyl. R is preferably hydrogen.

An alkoxy radical R¹ can be, for example, methoxy, ethoxy, isopropoxy,butoxy, hexyloxy, octyloxy or dodecyloxy. Preferred alkoxy radicals areC₁ -C₄ -alkoxy radicals.

An alkanoyloxy radical R¹ can be, for example, acetoxy, propionoxy,hexanoyloxy or stearoyloxy. A carbamoyloxy radical R¹ can bemonosubstituted or disubstituted carbamoyloxy, for examplemethylcarbamoyloxy, phenylcarbamoyloxy, dimethylcarbamoyloxy,dibutylcarbamoyloxy or di(dodecyl)carbamoyloxy.

R¹ is preferably hydrogen or a free valency.

An alkyl radical R² or R³ is, for example, methyl, ethyl, propyl,isopropyl, butyl, sec.butyl, isoamyl, hexyl, n-octyl, 2-ethylhexyl,1,1,3,3-tetramethylbutyl, decyl, undecyl, dodecyl, hexadecyl oroctadecyl. An alkoxyalkyl or hydroxyalkyl radical R² or R³ is, forexample, 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl,2-isopropoxyethyl, 3-butoxypropyl, 2-octyloxypropyl, 2-hydroxyethyl,2-hydroxypropyl or 2-hydroxybutyl. An alkenyl radical R² or R³ is, forexample, allyl, methallyl or 2-butenyl. An aralkyl radical R² or R³ canbe, for example, benzyl, 2-phenethyl, 3-phenylpropyl or1,1-dimethylbenzyl. An aryl or alkaryl radical R² or R³ can be, forexample, phenyl, naphthyl, tolyl, xylyl, 4-tert.-butylphenyl or4-octylphenyl. A cycloalkyl radical R² or R³ can be, for example,cyclopropyl, cyclopentyl, cyclohexyl or methylcyclohexyl. If R² and R³,together with the N atom to which they are bonded, form a heterocyclicring, this can be, for example, a piperidine, pyrrolidine, morpholine,piperidine or 4-alkylpiperidine ring.

The compounds containing a group I can be monomeric, oligomeric orpolymeric compounds. Monomeric compounds can be represented by thegeneral formula II ##STR5## in which m is an integer from 1 to 4, R¹ ishydrogen, C₂ -C₁₂ -alkoxy, C₂ -C₂₀ -alkanoyloxy, benzoyloxy, C₃ -C₂₅-carbamoyloxy or CN and R⁴ is hydrogen or an m-valent organic radical,or R¹ and R⁴ together are oxo-oxygen or a divalent organic radical, andR, R² and R³ are as defined above.

Oligomeric or polymeric compounds are those in which several groups ofthe formula I are bonded directly or via an intermediate member to anoligomer or polymer.

The following classes of compounds which can be prepared according tothe invention are of particular importance.

(a) Compounds of the formula III ##STR6## in which R, R² and R³ are asdefined above.

(b) Compounds of the formula IV ##STR7## in which R, R² and R³ are asdefined above.

(c) Compounds of the formula V ##STR8## in which n is a number from 1 to4, R⁸ is C₁ -C₄ -alkyl or C₂ -C₁₂ -alkanoyl, R⁹ is the n-valent radicalof a C₁ -C₂₀ -alcohol, C₂ -C₁₆ -diol, C₃ -C₁₈ -triol or C₄ -C₂₀ -tetrol,which can be interrupted by one or more oxygen atoms, and R, R² and R³are as defined above.

An alcohol radical R⁹ is, for example, the monovalent radical ofmethanol, ethanol, isopropanol, tert.-butanol,isopentanl,2-methoxyethanol, n-hexanol, cyclohexanol 2-ethylhexanol,2-ethylhexanol, isooctanol, cyclooctanol, n-decanol, benzyl alcohol,n-dodecanol or n-octadecanol, the divalent radical of ethylene glycol,propane-1,2-diol, butane-1,4-diol hexane-1,6-diol,2,2,4-trimethylhexane-1,6-diol, dodecane-1,12-diol, xylylene glycol,1,4-di(hydroxymethyl)cyclohexane, diethylene glycol or triethyleneglycol, the trivalent radical of glycerol, trimethylolethane ortrimethylolpropane or the tetravalent radical of pentaerythritol, theseradicals being formed by detaching n hydroxyl groups from the n-hydricalcohols.

(d) Compounds of the formula VI ##STR9## in which n is an integer from 1to 4, and, if n is 1, R⁵ is C₁ -C₁₈ -alkyl, which can be interrupted byone or more oxygen atoms, or is cyanoethyl, benzyl, glycidyl or amonovalent acyl radical of an aliphatic, cycloaliphatic, araliphatic,aromatic or heterocyclic carboxylic acid, aminocarboxylic acid, carbamicacid or phosphorus-containing acid, or, if n is 2, R⁵ is C₂ C₁₂-alkylene, C₄ -C₁₂ -alkenylene, xylylene or a divalent acyl radical ofan aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclicdicarboxylic acid, dicarbamic acid or phosphorus-containing acid, or, ifn is 3, R⁵ is a trivalent acyl radical of an aliphatic, cycloaliphatic,araliphatic, aromatic or heterocyclic tricarboxylic acid, tricarbamicacid or phosphorus-containing acid, or, if n is 4, R⁵ is a tetravalentacyl radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylicacid, and R, R² and R³ are as defined in claim 1.

Preferred compounds of the formula VI are those in which n is 1 or 2and, if n is 1, R⁵ is the monovalent acyl radical of an aliphaticcarboxylic acid having 2 to 18 C atoms, a cycloaliphatic carboxylic acidhaving 5 to 12 C atoms or an aromatic carboxylic acid having 7 to 15 Catoms, or, if n is 2, R⁵ is the divalent acyl radical of an aliphaticdicarboxylic acid having 2 to 36 C atoms, a cycloaliphatic or aromaticdicarboxylic acid having 8 to 16 C atoms or a cycloaliphatic or aromaticdicarbamic acid having 6 to 16 C atoms.

An alkyl radical R⁵ can be, for example, methyl, ethyl, propyl, n-butyl,sec.-butyl, tert.-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decyl,n-dodecyl or n-octadecyl. An alkylene radical R⁵ can be, for example,1,2-ethylene, 1,4-butylene, 1,8-octylene or 1,2-dodecylene. Analkenylene radical R⁵ can be, for example, 2-buten-1,4-ylene.

A monovalent acyl radical R⁵ can be, for example, the radical of acetic,propionic, butyric, isovaleric, acrylic, methacrylic, caproic, caprylic,lauric, palmitic, oleic, stearic, benzoic, 4-chlorobenzoic,4-octylbenzoic, toluic, phenoxyacetic, salicylic, 2-phenylpropionic,cyclohexanecarboxylic, furan-2-carboxylic, dimethylcarbamic,diphenylcarbamic, cyclohexylcarbamic or diphenylphosphinic acid.

A divalent acyl radical R⁵ can be, for example, the radical of oxalic,malonic, succinic, glutaric, diethylmalonic, dodecylsuccinic,dibenzylmalonic, adipic, sebacic, maleic, fumaric, diglycolic,isophthalic, terephthalic, diphenyl-4,4'-dicarboxylic,tetrahydrophthalic, hexahydroterephthalic,decahydronaphthalene-1,4-dicarboxylic, hexamethylenedicarbamic,toluylene-2,4-dicarbamic or phenylphosphonic acid.

A trivalent or tetravalent acyl radical R⁵ is, for example, the radicalof tricarballylic, trimellitic, nitrilotriacetic, phosphoric,phosphorous, pyromellitic, cyclohexanone-2,2,6,6-tetracarboxylic or4,4'-methylenediphthalic acid.

R⁵ can also be an acyl radical of a dicarboxylic or tricarboxylic acidsuch as is prepared industrially by dimerisation or trimerisation ofunsaturated fatty acids, for example linoleic acid, or by Diels-Alderaddition of acrylic acid onto linoleic acid.

(e) Compounds of the formula VII ##STR10## in which n is 1 or 2, R⁶ isC₁ -C₁₂ -alkyl, C₃ -C₁₂ -alkoxyalkyl, C₅ -C₈ -cycloalkyl, C₇ -C₉-aralkyl, C₂ -C₁₈ -alkanoyl, C₃ -C₅ -alkenoyl, benzoyl, C₂ -C₁₃-alkoxycarbonyl, C₇ -C₁₁ -aryloxycarbonyl or a group of the formula##STR11## and, if n is 1, R⁷ is C₁ -C₁₂ -alkyl, C₃ -C₁₂ -alkoxyalkyl, C₅-C₈ -cycloalkyl, C₃ -C₈ -alkenyl or cyanoethyl or, if R⁶ is alkanoyl,alkenoyl, benzoyl, alkoxycarbonyl, aryloxycarbonyl or carbamoyl, R⁷ canalso be hydrogen, or, if n is 2, R⁷ is C₂ -C₁₂ -alkylene, C₆ -C₁₅-arylene or xylylene, or if R⁶ is alkyl, cycloalkyl or aralkyl, R⁷ canalso be a divalent acyl radical of an aliphatic, cycloaliphatic oraromatic dicarboxylic acid or dicarbamic acid, or, if n is 1, R⁶ and R⁷,together with the N atom, are an imide radical of an aliphatic,cycloaliphatic or aromatic 1,2-dicarboxylic acid having 4 to 12 C atoms.

An alkyl radical R⁶ or R⁷ can be, for example, methyl, ethyl, isopropyl,n-butyl, tert.-butyl, isoamyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decylor n-dodecyl. An alkenyl radical R⁷ can be, for example, allyl,methallyl, but-2-en-1-yl or 1-dimethylallyl. A cycloalkyl radical R⁶ orR⁷ can be, for example, cyclopentyl, cyclohexyl, cycloheptyl orcyclooctyl.

An aralkyl radical R⁶ can be, for example, benzyl, phenethyl orphenylpropyl. An acyl radical R⁶ can be, for example, acetyl, propionyl,butyroyl, hexanoyl, octanoyl, lauroyl, palmitoyl, stearoyl, acryloyl,methacryloyl, benzoyl, ethoxycarbonyl, butoxycarbonyl,dodecyloxycarbonyl, phenoxycarbonyl or tolyloxycarbonyl.

An alkylene radical R⁷ can be, for example, 1,2-ethylene, 1,3-propyleneor tetra-, hexa-, octa- or dodecamethylene. An arylene radical R⁷ canbe, for example, phenylene, tolylene, diphenylene, diphenylenemethane ordiphenylene-2,2-propane. A divalent acyl radical R⁷ can be, for example,oxalyl, succinoyl, adipoyl, sebacoyl, cyclohexanedicarbonyl,terephthaloyl or hexamethylenedicarbamoyl.

If n is 1, R⁶ and R⁷, together with the N atom, can be a cyclic imideradical, for example a succinimide, maleimide, phthalimide orhexahydrophthalimide radical.

(f) Compounds of the formula VIII ##STR12## in which n is 1 or 2, and,if n is 1, R¹⁰ is C₂ -C₈ -alkylene or C₄ -C₂₂ -acyloxyalkylene, or, if nis 2, R¹⁰ is the group (--CH₂)₂ C(CH₂ -)₂, and R, R² and R³ are asdefined above.

In this formula, R¹⁰ can be, for example, 1,2-ethylene, 1,2-propylene,1,3-propylene, 2,2-dimethyl-1,3-propylene, 1,2-octylene,2-(acetoxymethyl)-2-ethyl-1,3-propylene,2-(lauroyloxymethyl)-2-ethyl-1,3-propylene,2-(butyroyloxymethyl)-2-methyl-1,3-propylene or 2-acetoxy-1,3-propylene.

(g) Compounds of the formula IX, X or XI ##STR13## in which n is 1 or 2,R¹¹ is hydrogen, C₁ -C₁₂ -alkyl, allyl, benzyl, glycidyl or C₂ -C₆-alkoxyalkyl, and, if n is 1, R¹² is hydrogen, C₁ -C₁₂ -alkyl, C₃ -C₅-alkenyl, C₇ -C₉ -aralkyl, C₅ -C₈ -cycloalkyl, C₂ -C₄ -hydroxyalkyl, C₃-C₆ -alkoxyalkyl, C₆ -C₁₀ -aryl or glycidyl, or, if n is 2, R¹² is C₂-C₁₂ -alkylene, C₆ -C₁₅ -arylene or C₄ -C₈ -alkenylene, and R, R² and R³are as defined above. are H, C₁ -C₁₂ -alkyl, C₇ -C₉ -aralkyl, or C₆ -C₁₀-aryl which is unsubstituted or substituted by halogen or C₁ -C₄ -alkyl,or R¹³ and R¹⁴ together are C₄ -C₁₁ -alkylene, and, if n is 1, R¹⁵ ishydrogen, C₁ -C.sub. 12 -alkyl, C₃ -C₅ -alkenyl, C₇ -C₉ -aralkyl, C₅ -C₈-cycloalkyl, glycidyl, C₂ -C₁₈ -alkanoyl, C₃ -C₅ -alkenoyl, benzoyl ortoluyl, or, if n is 2, R¹⁵ is C₂ -C₁₂ -alkylene, C₄ -C₈ -alkenylene orC₈ -C₁₄ -arylenedialkylene, and R, R² and R³ are as defined above.

In these formulae, R¹¹ and R₁₂ can be straightchain or branched alkyl,for example methyl, ethyl, isopropyl, n-butyl, sec.-butyl, tert.-butyl,n-hexyl, n-octyl, 2-ethylhexyl, n-decyl or n-dodecyl. An alkenyl radicalR¹² can be, for example, allyl, methallyl or 1,1-dimethylallyl. Analkoxyalkyl radical R¹¹ can be, for example, 2-methoxyethyl,2-butoxyethyl or 3-ethoxypropyl. A hydroxyalkyl or alkoxyalkyl radicalR¹² can be, for example, 2-hydroxyethyl, 2-hydroxypropyl or2-ethoxyethyl. An aralkyl radical R¹² can be, for example, benzyl,2-phenethyl or 1,1-dimethylbenzyl. A cycloalkyl radical R¹² can be forexample, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

An alkylene radical R¹² can be, for example 1,2-ethylene, 1,3-propyleneor tetra-, hexa-, octa-, deca- or dodeca-methylene. An alkenyleneradical R¹² can be, for example, but-2-en-1,4-ylene orhex-3-en-1,6-ylene. An arylene radical R¹² can be, for example,phenylene, naphthylene, diphenylene or 2,2-diphenylenepropane.

(h) Compounds of the formula XII ##STR14## in which n is 1 or 2, R¹⁶ isa group of the formula ##STR15## in which R, R² and R³ are as defined inclaim 1, Y is --O-- or --NR¹⁹ --, R¹⁹ is H, C₁ -C₁₂ -alkyl, C₃ -C₆-alkoxyalkyl, cyclohexyl, benzyl or a group ##STR16## A is C₂ -C₆-alkylene or --(CH₂)₃ --O- and p is zero or 1, and R¹⁷ has one of themeanings given for R¹⁶, or is --NR²⁰ R²¹, --OR²², --NHCH₂ OR²³ or--N(CH₂ OR²³)₂, in which R²⁰ has one of the meanings given for R¹⁹ andR²¹ is C₁ -C₁₂ -alkyl, cyclohexyl or benzyl, or R²⁰ and R²¹ together areC₄ -C₅ -alkylene or oxaalkylene, R²² is C₁ -C₁₂ -alkyl or phenyl and R²³is C¹ -C⁴ -alkyl, and, if n is 1, R¹⁸ has one of the meanings given forR¹⁶ and R¹⁷, or, if n is 2, R¹⁸ is a group -Y-Q-Y-, in which Q is C₂-C₁₂ -alkylene, C₄ -C₁₂ -alkylene which is interrupted by --O--, --NH--, --N-alkyl or by a group of the formula ##STR17## or Q iscyclohexylene, xylylene or phenylene.

In these formulae, R¹⁹, R²¹ and R²² can be straight-chain or branchedalkyl, for example methyl, ethyl, isopropyl, tert.-butyl, isoamyl,n-hexyl, 2-ethylhexyl, isononyl, n-decyl or n-dodecyl. An alkoxyalkylradical R¹⁹ can be, for example, 2-methoxyethyl, 2-butoxyethyl or2-ethoxybutyl.

An alkylene radical A or Q can be straight-chain or branched, forexample 1,2-ethylene, 1,3-propylene, 1,2-butylene or 1,2-hexylene. Q canmoreover also be, for example, hexa-, octa-, deca-, dodeca- or2,4,4-trimethylhexamethylene. An interrupted alkylene radical Q can be,for example, 3-oxapent-1,5-ylene, 3,6-dioxaoct-1,8-ylene,3-azapent-1,5-ylene or 3-(methylaza)pent-1,5-ylene.

R²⁰ and R²¹ together can be C₄ -C₅ -alkylene or oxaalkylene. In thiscase, they form, together with the N atom to which they are bonded, asaturated heterocyclic ring, for example a pyrrolidine, piperidine ormorpholine ring.

(i) Compounds of the formula XIII ##STR18## in which n is 1 or 2 and, ifn is 1, X is --CN, --COOR²⁴ or --CHCOOR²⁴, in which R²⁴ is C₁ -C₁₈-alkyl, benzyl or cyclohexyl, or, if n is 2, X is --COO--R²⁵ --OOC--, inwhich R²⁵ is C₂ -C₁₂ -alkylene, C₄ -C₁₀ -alkylene which is interruptedby --O-- or -N(C₁ -C₄ -alkyl)-, or C₆ -C₁₅ -cycloalkylene, p-xylylene orhexahydroxylylene, and R, R² and R³ are as defined above.

In this formula, R²⁴ can be a straight-chain or branched alkyl radical,for example methyl, butyl, n-octyl, tert.-octyl, 2-ethyloxyl, n-dodecylor octadecyl. An alkylene or interrupted alkylene radical R²⁵ can be,for example, 1,2-ethylene, 1,2-propylene, tetramethylene, hexamethylene,octamethylene, 2,4,4-trimethylhexamethylene,2,2-dimethyl-prop-1,3-ylene, 3-oxapent-1,5-ylene, 3,6-dioxaoct-1,8-yleneor 3-(methylaza)-pent-1,5-ylene. A cycloalkylene radical R²⁵ is, forexample, 1,4-cyclohexylene, 4,4'-dicyclohexylene,2,2-di(cyclohexylene)propane or decahydro-1,4-naphthylene.

(k) Oligomeric or polymeric compounds, the recurring molecular unit ofwhich contains a group of the formula I.

These compounds can be, for example, polymers or copolymers of acrylatesor acrylamides, methacrylates or methacrylamides, maleates or maleimidesor vinyl esters or vinyl ethers which contain a group of the formula I.However, the polymer can also be a condensation polymer, for example apolyester, polyamide, polyurethane, polyurea, polyaminotriazine orpolyether containing groups of the formula I in side chains. The groupsof the formula I in the side chains can be bonded directly or viaintermediate members to the main polymer chain.

In the case of copolymers, it is possible either for both monomers tocontain a group of the formula I or for only one component to containsuch a group.

Polymers of acrylates or methacrylates containing a group of the formulaI and copolymers thereof with alkyl acrylates or alkyl methacrylates arepreferred.

Those oligomeric or polymeric compounds having an average molecularweight not exceeding 20,000 are also preferred.

Of all the compounds of classes (a) to (k), those compounds containing agroup of the formula I in which R is hydrogen are in each casepreferred.

The process according to the invention consists of two reaction stages.In the first stage, the group of the formula Ia is converted into agroup of the formula Ib, which is converted into the group of theformula I in the second stage: ##EQU1##

As already stated, the two reaction stages can be carried out as aone-pot process, i.e. the intermediate of the structure Ib does not haveto be isolated.

Both stages are carried out in an inert solvent. Suitable solvents arehydrocarbons, for example benzene, toluene, xylene, cyclohexane or amixture of alkanes; esters, for example methyl acetate, ethyl acetate orbutyl acetate; and chlorinated solvents, for example methylene chloride,ethylene chloride or carbon tetrachloride. Those solvents in which allthe educts and the N-carbamoyl compound are readily soluble but the basehydrochloride is insoluble are particularly advantageous. In such acase, the hydrochloride can be separated off in a simple manner byfiltration.

Any proton acceptor can be used as the base, and organic amines areparticularly suitable. An excess of the educts, i.e. an excess of thecompound containing the group Ia in the first stage and an excess of thecompound R² --NH--R³ in the second stage, can also be used as the base.However, a tertiary amine is preferably used as the auxiliary base, forexample a trialkylamine, a dialkylaniline or a heterocyclic base.

In each case 1 molar equivalent of base is required for each of the tworeaction stages. If an excess of the educt containing the group of theformula Ia is used in the first stage, about 0.5 molar equivalent ofphosgene is added per molar equivalent of NH. However, if an auxiliarybase is used, about 1 mol of phosgene and at least 1 mol of auxiliarybase are added per molar equivalent of NH. Correspondingly, either atleast 2 molar equivalents of R² NHR³ or 1 molar equivalent of R² NHR³and at least 1 molar equivalent of the auxiliary base are added permolar equivalent of --COCl in the second reaction stage. A small excessof proton acceptor is generally advantageous.

Both reaction stages can be carried out at room temperature or slightlyelevated or reduced temperature, preferably at temperatures below 40 °C.The first reaction stage can already be carried out at surprisingly lowtemperatures, for example at -30° to +20° C.

The base hydrochloride formed can be filtered off after the firstreaction stage. However, it is simpler to continue directly with thesecond reaction stage, without intermediate filtration, and to filterthe mixture only after the second reaction stage. It is obvious to theexpert that both reaction stages must be carried out with exclusion ofmoisture, and the same applies to any intermediate filtration.

The product is isolated as a distillation residue from the filtrate ofthe second reaction stage by distilling off the solvent, and, ifnecessary, can be purified by recrystallisation or another conventionalmethod.

In the pure form, the 1-diorganocarbamoylpiperidines thus obtained arevery stable compounds and can be used as stabilisers for organicmaterials, in particular against damage to these materials by the actionof light. Such materials to be protected from light can be, for example,oils, fats, waxes, detergents or solvents, but the compounds which canbe prepared according to the invention are particularly suitable asstabilisers for organic polymers. The following classes of polymers areexamples of polymers which are sensitive towards the action of light andcan be stabilised by addition of the compounds which can be preparedaccording to the invention: 1. Polymers of monoolefins and diolefins,for example polyethylene (which may be crosslinked), polypropylene,polyisobutylene, polybut-1-ene, polymethylpent-1-ene, polyisoprene andpolybutadiene, and polymers of cycloolefins, for example of cyclopenteneor norbornene. 2. Mixtures of the polymers mentioned under (1), forexample mixtures of polypropylene with polyethylene or withpolyisobutylene. 3. Copolymers of monoolefins and diolefins with oneanother or with other vinyl monomers, for example ethylene/propylenecopolymers, propylene/but-1-ene copolymers, propylene/isobutylenecopolymers, ethylene/but-1-ene copolymers, propylene/butadienecopolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylatecopolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinylacetate copolymers and ethylene/acrylic acid copolymers and saltsthereof (isomers), and terpolymers of ethylene with propylene and adiene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene. 4.Polystyrene. 5. Copolymers of styrene or -methylstyrene with dienes oracrylic derivatives, for example styrene/butadiene,styrene/acrylonitrile, styrene/ethyl methacrylate,styrene/butadiene/ethyl acrylate and styrene/acrylonitrile/methylacrylate; high impact strength mixtures of styrene copolymers andanother polymer, for example a polyacrylate, a diene polymer, or anethylene/propylene/diene terpolymer; and block copolymers of styrene,for example styrene/butadiene/styrene, styrene/isoprene/styrene,styrene-ethylene/butylene-styrene andstyrene-ethylene/propylene-styrene. 6. Graft copolymers of styrene, forexample styrene on polybutadiene, styrene and acrylonitrile onpolybutadiene, styrene and maleic anhydride on polybutadiene, styreneand alkyl acrylates or alkyl methacrylates on polybutadiene, styrene andacrylonitrile on ethylene/propylene/diene terpolymers, styrene andacrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styreneand acrylonitrile on acrylate/butadiene copolymers, and mixtures thereofwith the copolymers listed under (5), for example those known assocalled ABS, MBS, ASA or AES polymers. 7. Halogen-containing polymers,for example polychloroprene, chlorinated rubber, chlorinated orchlorosulfonated polyethylene and epichlorohydrin homopolymers andcopolymers, in particular polymers of halogen-containing vinylcompounds, for example polyvinyl chloride, polyvinylidene chloride,polyvinyl fluoride and polyvinylidene fluoride; and copolymers thereof,such as vinyl chloride/vinylidene chloride, vinyl chloride/vinyl acetateand vinylidene chloride/vinyl acetate. 8. Polymers which are derivedfrom α,β-unsaturated acids and derivatives thereof, such aspolyacrylates, polymethacrylates, polyacrylamides andpolyacrylonitriles. 9. Copolymers of the monomers listed under (8) withone another and with other unsaturated monomers, for exampleacrylonitrile/butadiene copolymers, acrylonitrile/alkyl acrylatecopolymers, acrylonitrile/alkoxyalkyl acrylate copolymers,acrylonitrile/vinyl halide copolymers, methyl methacrylate/styrenecopolymers and acrylonitrile/alkyl methacrylate/butadiene terpolymers.10. Polymers which are derived from unsaturated alcohols and amines ortheir acyl derivatives or acetals, such as polyvinyl alcohol, polyvinylacetate, stearate, benzoate or maleate, polyvinyl butyrate, polyallylphthalate and polyallylmelamine. 11. Homopolymers and copolymers ofcyclic ethers, such as polyalkylene glycols, polyethylene oxide,polypropylene oxide and copolymers thereof with bisglycidyl ethers. 12.Polyacetals, such as polyoxymethylene, and those polyoxymethylenescontaining comonomers, for example ethylene oxide. 13. Polyphenyleneoxides and sulfides and mixtures thereof with styrene polymers. 14.Polyurethanes which are derived from polyethers, polyesters andpolybutadienes with terminal hydroxyl groups on the one hand andaliphatic or aromatic polyisocyanates on the other hand, andintermediates thereof (polyisocyanates, polyols and prepolymers). 15.Polyamides and copolyamides which are derived from diamines anddicarboxylic acids and/or aminocarboxylic acids or the correspondinglactams, such as polyamide 4, polyamide 6, polyamide 6/6, polyamide6/10, polyamide 11, polyamide 12,poly-2,4,4-trimethylhexamethyleneterephthalamide andpoly-m-phenylene-isophthalamide, and copolymers thereof with polyethers,for example with polyethylene glycol, polypropylene glycol andpolytetramethylene glycol. 16. Polyureas, polyimides, polyamide-imidesand polybenzimidazoles. 17. Polyesters which are derived fromdicarboxylic acids and diols and/or hydroxycarboxylic acids or thecorresponding lactones, such as polyethylene terephthalate, polybutyleneterephthalate, poly-1,4-dimethylolcyclohexane terephthalate,poly-[2,2-bis-(4-hydroxyphenyl)-propane]-terephthalate andpolyhydroxybenzoates, and block polyether/esters which are derived frompolyethers with terminal hydroxyl groups, dialcohols and dicarboxylicacids. 18. Polycarbonates. 19. Polysulfones and polyether-sulfones. 20.Crosslinked polymers which are derived from aldehydes on the one handand phenols, urea and melamine on the other hand, such asphenol/formaldehyde resins, urea/formaldehyde resins andmelamine/formaldehyde resins. 21. Drying and non-drying alkyd resins.22. Unsaturated polyester resins which are derived from copolyesters ofsaturated and unsaturated dicarboxylic acids with polyhydric alcohols,and vinyl compounds as crosslinking agents, as well ashalogen-containing modifications thereof which are difficult to ignite.23. Crosslinkable acrylic resins which are derived from substitutedacrylates, for example from epoxy acrylates, urethane-acrylates orpolyester-acrylates. 24. Alkyd resins, polyester resins and acrylateresins which are crosslinked with melamine resins, urea resins,polyisocyanates or epoxide resins. 25. Crosslinked epoxide resins whichare derived from polyepoxides, for example from bis-glycidyl ethers orcycloaliphatic diepoxides. 26. Naturally occurring polymers, such ascellulose, natural rubber and gelatin, and their polymer-analogouschemically modified derivatives, such as cellulose acetates, propionatesand butyrates, and the cellulose ethers, such as methylcellulose.

The stabilisers are added to the plastics in a concentration of 0.01 to5% by weight, based on the material to be stabilised. Preferably, 0.03to 1.5% by weight, and particularly preferably 0.2 to 0.6% by weight, ofthe compounds, based on the material to be stabilised, are incorporatedinto this material.

The incorporation can be effected during or after polymerisation, forexample by mixing the compounds and, where appropriate, other additivesinto the melt by the conventional methods of the art, before or duringshaping, or by applying the dissolved or dispersed compounds to thepolymer, if necessary with subsequent evaporation of the solvent.

The compounds can also be added in the form of a master batch containingthem in a concentration of, for example, 2.5 to 25% by weight to theplastics to be stabilised.

In addition to the compounds of the formula I, other known stabiliserscan also be added to the plastics. These stabilisers can be, forexample, antioxidants, light stabilisers or metal deactivators, orco-stabilisers, for example those of the phosphorous acid ester type.Other additives conventional in plastics technology, for exampleflameproofing agents, antistatic agents, plasticisers, lubricants,blowing agents, pigments, reinforcers or fillers, can also be added. Thefollowing compounds are specific examples of such known and conventionaladditives:

1. Antioxidants

1.1. Alkylated monophenols such as 2,6-di-tert.-butyl-4-methylphenol,2-tert.-butyl-4,6-dimethylphenol, 2,6-di-tert.-butyl-4-ethylphenol,2,6-di-tert.-butyl-4-n-butylphenol, 2,6-di-tert.-butyl-4-i-butylphenol,2,6-di-cyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-di-octadecyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol and2,6-di-tert.-butyl-4-methoxymethylphenol. 1.2. Alkylated hydroquinones,such as 2,6-di-tert.-butyl-4-methoxyphenol,2,5-di-tert.-butyl-hydroquinone, 2,5-di-tert.-amyl-hydroquinone and2,6-diphenyl-4-octadecyloxyphenol. 1.3. Hydroxylated thiodiphenylethers, such as 2,2'-thio-bis-(6-tert.-butyl-4-methylphenol),2,2'-thio-bis-(4-octylphenol),4,4'-thio-bis-(6-tert.-butyl-3-methylphenol) and4,4'-thio-bis-(6-tert.-butyl-2-methylphenol). 1.4.Alkylidene-bisphenols, such as2,2'-methylene-bis-(6-tert.-butyl-4-methylphenol),2,2'-methylene-bis-(6-tert.-butyl-4-ethylphenol),2,2'-methylene-bis-[4-methyl-6-(α-methylcyclohexyl)-phenol],2,2'-methylene-bis-(4-methyl-6cyclohexylphenol),2,2'-methylene-bis-(6-nonyl-4-methylphenol),2,2'-methylene-bis-(4,6-di-tert.-butylphenol),2,2'-ethylidene-bis-(4,6-di-tert.-butylphenol),2,2'-ethylidene-bis-(6-tert.-butyl-4-isobutylphenol),4,4'-methylene-bis-(2,6-di-tert.-butylphenol), 4,4'-methylene-bis-(6-tert.-butyl-2-methylphenol),1,1-bis-(5-tert.-butyl-4-hydroxy-2-methylphenyl)-butane,2,6-di-(3-tert.-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris-(5-tert.-butyl-4-hydroxy-2-methylphenyl)-butane,1,1-bis-(5-tert.-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane, ethylene glycolbis-[3,3-bis-(3'-tert.-butyl-4'-hydroxyphenyl)butyrate],di-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene anddi-[2-(3'-tert.-butyl-2'-hydroxy-5'-methyl-benzyl)-6-tert.-butyl-4-methyl-phenyl]terephthalate.1.5. Benzyl compounds, such as1,3,5-tri-(3,5-di-tert.-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,di-(3,5-di-tert.-butyl-4-hydroxybenzyl) sulfide, isooctyl3,5-di-tert.-butyl-4-hydroxybenzyl-mercaptoacetate,bis-(4-tert.-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiol-terephthalate,1,3,5-tris-(3,5-di-tert.-butyl-4-hydroxybenzyl) isocyanurate,1,3,5-tris-(4-tert.-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,dioctadecyl 3,5-di-tert.-butyl-4-hydroxybenzyl-phosphonate and thecalcium salt of monoethyl3,5-di-tert.-butyl-4-hydroxybenzyl-phosphonate. 1.6. Acylaminophenols,such as 4-hydroxy-lauric acid anilide, 4-hydroxy-stearic acid anilideand2,4-bis-octylmercapto-6-(3,5-di-tert.-butyl-4-hydroxyanilino)-s-triazine.1.7. Esters of β-(3,5-di-tert.-butyl-4-hydroxyphenyl)propionic acid withmonohydric or polyhydric alcohols, for example with methanol,octadecanol, hexane-1,6-diol, neopentylglycol, diethylene thioglycol,diethylene glycol, triethylene glycol, pentaerythritol,tris-hydroxyethyl isocyanurate or di-hydroxyethyl-oxalic acid diamide.1.8. Esters of β-(5-tert.-butyl-4-hydroxy-3-methylphenyl)propionic acidwith monohydric or polyhydric alcohols, for example with methanol,octadecanol, hexane-1,6-diol, neopentylglycol, diethylene thioglycol,diethylene glycol, triethylene glycol, pentaerythritol,tris-hydroxyethyl isocyanurate or di-hydroxyethyl-oxalic acid diamide.1.9. Amides of β-(3,5-di-tert.-butyl-4-hydroxyphenyl)propionic acid, forexampleN,N'-di-(3,5-di-tert.-butyl-4-hydroxyphenylpropionyl)-hexamethylenediamine,N,N'-di-(3,5-di-tert.-butyl-4-hydroxyphenylpropionyl)-trimethylenediamineand N,N'-di-(3,5-di-tert.-butyl-4-hydroxyphenylpropionyl)-hydrazine.

2. UV Absorbers and light stabilisers 2.1.2-(2'-Hydroxyphenyl)-benzotriazoles, for example the 5'-methyl,3',5'-di-tert.-butyl, 5'-tert.-butyl, 5'-(1,1,1,3,3-tetramethylbutyl),5-chloro-3',5'-di-tert.-butyl, 5-chloro-3'-tert.-butyl-5'-methyl,3'-sec.-butyl-5'-tert.butyl, 4'-octoxy and 3',5'-di-tert.-amylderivatives. 2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy,4-methoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy,4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives. 2.3.Esters of substituted or unsubstituted benzoic acids, for example4-tert.-butyl-phenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis-(4-tert.-butylbenzoyl)-resorcinol,benzoylresorcinol and 2,4-di-tert.-butyl-phenyl3,5-di-tert.-butyl-4-hydroxybenzoate. 2.4. Acrylates, for example ethylor isooctyl α-cyano-β,β-diphenylacrylate, methylα-carbomethoxy-cinnamate, methyl or butylα-cyano-β-methyl-p-methoxy-cinnamate, methylα-carbomethoxy-p-methoxy-cinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methyl-indoline. 2.5. Nickelcompounds, for example nickel complexes of2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)-phenol], such as the 1:1 or1:2 complex, with or without additional ligands, such as n-butylamine,triethanolamine or N-cyclohexyl-diethanolamine, nickeldibutyl-dithiocarbamate, nickel salts of monoalkyl, such as methyl orethyl, 4-hydroxy-3,5-di-tert.-butylbenzylphosphonates, nickel complexesof ketoximes, such as of 2-hydroxy-4-methyl-phenyl undecyl ketone oxime,and nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with orwithout additional ligands. 2.6. Sterically hindered amines, for examplebis-(2,2,6,6-tetramethylpiperidyl) sebacate,bis-(1,2,2,6,6-pentamethylpiperidyl) sebacate,bis-(1,2,2,6,6-pentamethylpiperidyl)n-butyl-3,5-di-tert.-butyl-4-hydroxybenzyl-malonate, the condensationproduct of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine andsuccinic acid, the condensation product ofN,N'-(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-tert.-octylamino-2,6-dichloro-1,3,5-s-triazine, andtris-(2,2,6,6-tetramethyl-4-piperidyl) nitriloacetate. 2.7. Oxalic aciddiamides, for example 4,4'-di-octyloxyoxanilide,2,2'-dioctyloxy-5,5'-di-tert.-butyl-oxanilide,2,2'-di-dodecyloxy-5,5'-di-tert.-butyl-oxanilide,2-ethoxy-2'-ethyl-oxanilide, N,N'-bis-(3-dimethylaminopropyl)-oxalamide,2-ethoxy-5-tert.-butyl-2'-ethyl-oxanilide and its mixture with2-ethoxy-2'-ethyl-5,4'-di-tert.-butyl-oxanilide, and mixtures of ortho-and para-methoxy- and of o- and p-ethoxy-disubstituted oxanilides. 3.Metal deactivators, for example N,N'-diphenyloxalic acid diamide,N-salicylal-N'-salicyloylhydrazine, N,N'-bis-salicyloylhydrazine,N,N'-bis-(3,5-di-tert.-butyl-4-hydroxyphenylpropionyl)-hydrazine,3-salicyloylamino-1,2,4-triazole and bis-benzylidene-oxalic aciddihydrazide. 4. Phosphites and phosphonites, for example triphenylphosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites,tri-(nonylphenyl) phosphite, trilauryl phosphite, trioctadecylphosphite, distearyl pentaerythritol diphosphite,tris-(2,4-di-tert.-butylphenyl) phosphite, diisodecyl pentaerythritoldiphosphite, di-(2,4-di-tert.-butylphenyl) pentaerythritol diphosphite,tristearyl sorbitol triphosphite andtetrakis-(2,4-di-tert.-butylphenyl)-4,4'-biphenylene diphosphonite. 5.Compounds which destroy peroxide, for example esters ofβ-thio-dipropionic acid, for example the lauryl, stearyl, myristyl ortridecyl ester, mercaptobenzimidazole, the zinc salt of2-mercaptobenzimidazole, zinc dibutyl-dithiocarbamate, dioctadecyldisulfide and pentaerythritol tetrakis-(β-dodecylmercapto)-propionate.6. Polyamide stabilisers, for example copper salts in combination withiodides and/or phosphorus compounds and salts of divalent manganese. 7.Basic co-stabilisers, for example melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes and alkali metal andalkaline earth metal salts of higher fatty acids, for example Castearate, Zn stearate, Mg stearate, Na ricinoleate, K palmitate,antimony pyrocatecholate and tin pyrocatecholate. 8. Nucleating agents,for example 4-tert.-butylbenzoic acid, adipic acid and diphenylaceticacid. 9. Fillers and reinforcers, for example calcium carbonates,silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate,metal oxides and hydroxides, carbon black and graphite. 10. Otheradditives, for example plasticisers, lubricants, emulsifiers, pigments,fluorescent brighteners, flameproofing agents, antistatic agents andblowing agents.

The invention thus also relates to the organic polymers which have beenstabilised by the addition of 0.01 to 5% by weight of a compoundprepared according to the invention and which, where appropriate, mayalso contain other known and conventional additives. The plastics thusstabilised can be used in many diverse forms, for example as films,fibres, tapes or profiles, or as binders for varnishes, adhesives orputties.

The compounds prepared according to the invention can also be used asintermediates for the preparation of other polyalkylpiperidinederivatives which likewise have a light stabilising action. By reactionswhich do not modify the 1-diorganocarbamoyl group, it is possible toobtain compounds which cannot be prepared by direct phosgenation.

For example, a compound of the formula XIV can be converted byhydrolysis into a 1-carbamoyl-4-hydroxypiperidine XV, which is notreadily accessible by direct phosgenation of4-hydroxy-tetramethylpiperidine: ##STR19##

Alternatively, XV can also be prepared by reducing the corresponding4-oxo compound XVI: ##STR20##

Reduction with complex borohydrides or catalytic hydrogenation issuitable in this case.

The 4-hydroxy compound XV can in turn be further reacted, for example byetherification, esterification or carbamoylation of the hydroxyl group.

Another example of transformation of compounds containing a group I ispolymerisation or polycondensation with the formation of polymeric oroligomeric products. Although the resulting polymers, which contain agroup I, can also be prepared from the corresponding polymers containinga group Ia by the phosgenation process described above, polymerisationof suitable monomers containing a group of the formula I can in manycases be the more advantageous route.

Overall, a large number of novelN-diorganocarbamoyl-polyalkylpiperidines have become accessible by thecarbamoylation process according to the invention and by transformationof the resulting products into corresponding secondary products.

These N-diorganocarbamoyl-polyalkylpiperidines belong, in particular, tothe following classes of compounds:

(1) the compounds of the formula III listed above as group (a);

(2) the compounds of the formula IV listed above as group (b);

(3) the compounds of the formula V listed above as group (c), and thosecompounds of the formula V in which R⁸ is hydrogen;

(4) the compounds of the formula VI ##STR21## in which n is an integerfrom 1 to 4, and, if n is 1, R⁵ is hydrogen, or, if n is 2, R⁵ is C₂-C₁₂ -alkylene, C₄ -C12-alkenylene, xylylene or a divalent acyl radicalof an aliphatic or cycloaliphatic dicarboxylic acid, dicarbamic acid orphosphorus-containing acid, or, if n is 3, R⁵ is a trivalent acylradical of an aliphatic, cycloaliphatic, araliphatic, aromatic orheterocyclic tricarboxylic acid, tricarbamic acid orphosphorus-containing acid, or, if n is 4, R⁵ is a tetravalent acylradical of an aliphatic, cycloaliphatic or aromatic tetracarboxylicacid, and R, R² and R³ are as defined above;

(5) compounds of the formula VII ##STR22## in which n is 1 or 2, R⁶ isC₁ -C₁₂ -alkoxyalkyl, C₅ -C₇ -cycloalkyl, C₇ -C₉ -aralkyl, C₂ -C₁₈-alkanoyl, C₃ -C₅ -alkenoyl benzoyl, C₂ -C₁₃ -alkoxycarbonyl or C₇ -C₁₁-aryloxycarbonyl and, if n is 1, R is H, C₁ -C₁₂ -alkyl, C₃-C12-alkoxyalkyl, C₅ -C₈ -cycloalkyl, C₃ -C₈ -alkenyl, glycidyl orcyanoethyl, or, if n if 2 R⁷ is C₂ -C₁₂ -alkylene, C₆ -C₁₅ -arylene,xylylene or a --CH₂ --CH(OH)--CH₂ -- or --CH --CH(OH)--CH --O--D--O--CH₂--CH(OH)--CH₂ -- group, in which D is C₂ -C₁₀ -alkylene, C₆ -C₁₅-arylene or C₆ -C₁₂ -cycloalkylene, or, if R⁶ is alkyl, cycloalkyl oraralkyl, R⁷ can also be a divalent acyl radical of an aliphatic,cycloaliphatic or aromatic dicarboxylic acid or dicarbamic acid, or, ifn is 1, R⁶ and R⁷, together with the N atom, are an imide radical of analiphatic, cycloaliphatic or aromatic 1,2-dicarboxylic acid having 4 to12 C atoms;

(6) compounds of the formula VIII ##STR23## in which n is 1 or 2, and,if n is 1, R¹⁰ is C₂ -C₈ -alkylene or α-hydroxyalkylene or C₄ -C₂₂-acyloxyalkylene, or, if n is 2, R¹⁰ is the (--CH₂)₂ C(CH₂ --)₂ group,and R, R² and R³ are as defined above;

(7) compounds of the formula IX, ##STR24## in which n is 1 or 2, R¹¹ ishydrogen, C₁ -C₁₂ -alkyl, allyl, benzyl, glycidyl or C₂ -C₆-alkoxyalkyl, and, if n is 1, R¹² is hydrogen, C₁ -C₁₂ -alkyl, C₃ -C₅-alkenyl, C₇ -C₉ -aralkyl, C₅ -C₈ -cycloalkyl, C₂ -C₄ -hydroxyalkyl, C₃-C₆ -alkoxyalkyl, C₆ -C₁₀ -aryl or glycidyl, or, if n is 2, R¹² is C₂-C₁₂ -alkylene, C₆ -C₁₅ -arylene, C₄ -C₈ -alkenylene or a--CH--CH(OH)--CH₂ --O--D--O--CH₂ --CH(OH)--CH₂ -- group, in which D isC₂ -C₁₂ -alkylene, C₆ -C₁₅ -arylene or C₆ -C₁₂ cycloalkylene, and R, R²and R³ are as defined above;

(8) compounds of the formula XII ##STR25## in which n is 1 or 2, R¹⁶ isa group of the formula ##STR26## in which R, R² and R³ are as definedabove, Y is --O-- or --NR¹⁹ --, R¹⁹ is H, C₁ -C₁₂ -alkyl, C₂ -C₄-hydroxyalkyl, C₃ -C₆ -alkoxyalkyl, cyclohexyl, benzyl or a group##STR27## A is C₂ -C₆ -alkylene or --(CH₂)₃ --O-- and p is zero or 1,and R¹⁷ has one of the meanings given for R¹⁶ or is --NR²⁰ R²¹, --OR²²,--NHCH₂ OR²³ or --N(CH₂ OR²³)₂, in which R²⁰ has one of the meaningsgiven for R¹⁹ and R²¹ is C₁ -C₁₂ -alkyl, cyclohexyl or benzyl, or R²⁰and R²¹ together are C₄ -C₅ -alkylene or oxaalkylene, R²² is hydrogen,C₁ -C₁₂ -alkyl or phenyl and R²³ is hydrogen or C₁ -C₄ -alkyl, and, if nis 1, R¹⁸ has one of the meanings given for R¹⁶ and R¹⁷, or, if n is 2,R¹⁸ is a --Y--Q--Y-- group, in which Q is C₂ -C₁₂ -alkylene, C₄ -C₁₂-alkylene which is interrupted by --O--, --NH--, --N-alkyl or by a groupof the formula ##STR28## or Q is cyclohexylene, xylylene or phenylene;

(9) compounds of the formula XIII ##STR29## in which n is 1 or 2, and,if n is 1, X is --CN, --COOR²⁴, --CH₂ NH₂, --CH₂ OH or --CH₂ COOR²⁴, inwhich R²⁴ is C₁ -C₁₈ -alkyl, benzyl or cycloalkyl, or, if n is 2, X is--CO--O--R²⁵ --O--CO--, in which R²⁵ is C₂ -C₁₂ -alkylene, C₄ -C₁₀-alkylene which is interrupted by --O-- or --N(C₁ C₄ -alkyl)--, or C₆-C₁₅ -cycloalkylene, p-xylylene or hexahydroxylylene, and R, R² and R³are as defined above; and

(10) oligomeric or polymeric compounds, the recurring molecular unit ofwhich contains a group of the formula I, in particular those having anaverage molecular weight not exceeding 20,000, preferably thosecompounds which are polymers of acrylates or methacrylates containing agroup of the formula I, or copolymers thereof with alkyl(meth)acrylates.

All these novel piperidine compounds can be used in the manner describedabove as stabilisers for organic materials, in particular as lightstabilisers for organic polymers.

The examples which follow describe the process according to theinvention and specific compounds thereby obtainable, as well as theconversion of such compounds into other compounds containing a group ofthe formula I by secondary reactions.

EXAMPLE 1 Carbamoylation in ethyl acetate EXAMPLE 1

A solution of 24.7 g (0.25 mol) of phosgene in about 150 ml of ethylacetate is added dropwise to a solution of 99.7 g (0.5 mol) of4-acetoxy-2,2,6,6-tetramethylpiperidine in 400 ml of ethyl acetate at20°-22° in the course of 6 hours, with stirring. After the reactionmixture has been stirred for another 2 hours at room temperature, 63 ml(0.6 mol) of diethylamine are added dropwise in the course of about 30minutes. The reaction mixture is stirred at room temperature for another14 hours and is filtered and the salt residue is washed thoroughly withhexane. The combined filtrates are washed twice with water, three timeswith ice-cold N hydrochloric acid and again with water and dried oversodium sulfate and the solvent is distilled off in a vacuum rotaryevaporator. The crude product is recrystallised from diisopropyl etherto give pure 1-diethyl-carbamoyl-4-acetoxy-2,2,6,6-tetramethylpiperidine (Compound No. 1) of meltingpoint 58°-60°.

Elementary analysis:

C₁₆ H₃₀ N₂ O₃ Calculated: C, 64.40; H, 10.13; N,9.39%.

(298.4) Found: C, 64.6; H, 10.0; N, 9.3%.

The ¹ H-NMR spectrum is in agreement with the given structure.

The N-carbamoyl-piperidines listed in Table 1 are prepared by a methodanalogous to that described in Example 1.

                                      TABLE 1                                     __________________________________________________________________________    Compound                                               Physical               No.    Name             Formula                        Data                   __________________________________________________________________________    2      1-Dimethylcarbamoyl- 2,2,6,6-tetramethylpiperidine                                              ##STR30##                     Melting point                                                                 69-70°          3      1-Diethylcarbamoyl-2,2,6,6- tetramethylpiperidine                                               ##STR31##                     Melting point                                                                 32-34°          4      1-Diethylcarbamoyl-2,2,6,6- tetramethyl-4-benzoyloxypiperidine                                  ##STR32##                     Melting point                                                                 44-46°          5      1-Diethylcarbamoyl-2,2,6,6- tetramethylpiperid-4-one                                            ##STR33##                     Melting point                                                                 80-82°          6      1-Di-(2-hydroxyethyl)- carbamoyl-2,2,6,6-tetra- methylpiperidine                                ##STR34##                     oil                    7      3-Ethyl-3-acetoxymethyl- 8,8,10,10-tetramethyl-9- diethylcarbamoyl-           1,5-dioxa- 9-aza-spiro[5.5]decane                                                               ##STR35##                     Melting point                                                                 80-81°          8      N,N'dimethyl-N,N'bis-                           m.p.                          tetramethylpiperidine-                          234-236°               carbonyl)-ethylenediamine                                              9      8-morpholinocarbonyl-                           m.p.                          1,3,8-triaza-2,4-dioxo-3-                       152-153°               dodecyl-7,7,9,9-tetra-                                                        methylspiro[4,5]-decane                                                10     1-piperidinocarbonyl-4-                         m.p.                          (β-piperidinopropionoxy)-                   84-86°                2,2,6,6-tetramethyl-                                                          piperidine                                                             __________________________________________________________________________

EXAMPLE 2 Carbamoylation in toluene

To a solution of phosgene in toluene (24.7 ml of a 20% solution,corresponding to 0.05 mol of phosgene) is added dropwise at -30°, withinone hour, the solution of 14.2 g (0.1 mol) of2,2,6,6-tetramethylpiperidine in 25 ml of toluene. Stirring ismaintained at 0° for a further 2 hours; there are then added dropwise,within 2 hours, 26.7 g (0.11 mol) of di-n-octylamine in 25 ml oftoluene, and the mixture is subsequently stirred for 16 hours at roomtemperature. In further processing, the salt which has precipitated isfiltered off; the filtrate is afterwards repeatedly washed with a smallamount of water, dried over sodium sulfate, and the solvent iscompletely distilled off in a water-jet vacuum. The crude compound isfurther purified by column chromatography on silica gel (eluant:hexane/diethyl ether 9:1) to obtain the pure1-di-n-octylcarbamoyl-2,2,6,6-tetramethylpiperidine (compound No. 11) asa viscous liquid; n_(D) ²⁰ : 1.4728.

The ¹ H-NMR spectrum of the resulting compound is in agreement with thegiven structure.

Elementary analysis:

C₂₆ H₅₂ N₂ O Calculated: C, 76.41; H, 12.83; N, 6.85%.

(408.7) Found: C, 76.5; H, 12.6; N, 6.8%.

EXAMPLE 3 Carbamoylation with the addition of an auxiliary base

The solution of 39.6 g (0.4 mol) of phosgene in about 300 ml of ethylacetate is added dropwise at 0°-5° C. within about 6 hours, withstirring, to a solution of 84.5 g (0.4 mol) of4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 0.2 g ofdi-tert-butyl-p-cresol and 129.3 g (1.0 mol) of diisopropylethylamine in300 ml of ethyl acetate. After a further 3 hours' stirring at roomtemperature, there is added dropwise to the white suspension at about20°, in the course of one hour (with slight external cooling andvigorous stirring), a solution of 35.7 g (0.41 mol) of morpholine in 40ml of ethyl acetate. The reaction mixture is stirred for a further 6hours at room temperature, and is then filtered; the salt residue iswell washed with hexane, and the filtrate is freed, in a vacuum rotaryevaporator, from the solvents and the unreacted diisopropylethylamine.The residue is dissolved in methylene chloride, and this solution iswashed twice with water, three times with cold N hydrochloric acid andagain twice with water; the organic phase is subsequently dried oversodium sulfate, and the solvent is distilled off in vacuo. The crudeproduct, solidifying in crystalline form, is recrystallised indiisopropyl ether to thus obtain pure1-morpholinocarbonyl-4-acryloyloxy-2,2,6,6-tetramethylpiperidine, m.p.129°-130° (compound No. 12).

Elementary Analysis:

C₁₇ H₂₈ N₂ O₄ Calculated: C, 62.94; H, 8.70; N, 8.64%.

(324.4) Found: C, 63.2; H, 8.8; N, 8.4%.

The ¹ NMR spectrum is in agreement with the given structure.

1-Piperidonocarbonyl-4-acryloyloxy-2,2,6,6-tetramethylpiperidine, m.p.90°-92° (compound No. 13) is produced in an analogous manner.

EXAMPLE 4 Hydrolysis to 4-hydroxypiperidine

A solution of 5.7 g of sodium hydroxide in 50 ml of methanol is added toa solution of 41.8 g of1-diethylcarbamoyl-4-acetoxy-2,2,6,6-tetramethylpiperidine [0.14 mol(compound No. 1)] in 200 ml of methanol. The reaction mixture is stirredfor 16 hours at room temperature, and is then freed from methanol in thevacuum rotary evaporator; the residue is subsequently dissolved inmethylene chloride, and washed three times with water. The organic phaseis dried over sodium sulfate; it is afterwards filtered, and themethylene chloride is distilled off. The crystalline residue isrecrystallised in diisopropyl ether to thus obtain pure1-diethylcarbamoyl-4-hydroxy-2,2,6,6-tetramethylpiperidine (compound No.14), m.p. 118°-119°.

Elementary analysis:

C₁₄ H₂₈ N₂ O₂ Calculated: C, 65.59; H, 11.01; N, 10.93%.

(256.4) Found: C, 65.6; H, 10.8; N, 11.0%.

The ¹ H-NMR spectrum is in agreement with the given structure of thecompound obtained.

There is produced in an analogous manner by hydrolysis of the compoundNo. 9: 1-morpholinocarbonyl-4-hydroxy-2,2,6,6-tetramethylpiperidine,m.p. 142°-143° (compound No. 15); and by hydrolysis of the compound No.10: 1-piperidinocarbonyl-4-hydroxy-2,2,6,6-tetramethylpiperidine(compound No. 16).

EXAMPLE 5 Reaction of 4-hydroxypiperidines

To a solution of 15.4 g of1-diethylcarbamoyl-4-hydroxy-2,2,6,6-tetramethylpiperidine (0.06 mol)(compound No. 14) and 6.9 g (0.03 mol) of dimethyl sebacate in 200 ml ofxylene is added 0.1 ml of tetrabutyl orthotitanate, and the mixture isslowly heated, in a gently stream of nitrogen, to a maximum temperatureof 145°, the methanol formed being continuously distilled off, andfinally also the xylene being completely distilled off slowly in thecourse of 8 hours. After cooling, the reaction mixture is dissolved inmethylene chloride; the solution is then washed with water, dried oversodium sulfate, and the solvent is subsequently distilled off. The crudecompound, solidifying in crystalline form, is recrystallised frompentane to thus obtain purebis-(1-diethylcarbamoyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate(compound No. 17), m.p. 72°-73°.

Elementary analysis:

C₃₈ H₇₀ N₄ O₆ Calculated: C, 67.22; H, 10.39; N, 8.25%.

(679.0) Found: C, 67.0; H, 10.5; N, 8.1% .

The ¹ NMR spectrum of the compound obtained is well compatible with thegiven structure.

There is obtained in an analogous manner by reaction of the compound No.14 with dimethyl adipate:bis-(1-diethylcarbamoyl-2,2,6,6-tetramethylpiperidin-4-yl)adipate, m.p.104°-105° (compound No. 18).

By an analogous reaction of the compound No. 16 with an excess ofdiethyl carbonate and subsequently with hexanediol-1,6 in the molarratio of 2:1, there is obtainedhexamethylene-bis(1-piperidinocarbonyl-2,2,6,6-tetramethylpiperidin-4-yl)carbonate (compound No. 19), m.p. 128°-130°.

Reaction of the compound No. 15 with hexamethylenediisocyanate yieldsO,O'-bis(1-morpholinocarbonyl-2,2,6,6-tetramethyl-4-piperidinyl)-N,N'-hexamethylenedicarbonate (compound No. 20), which melts at 128°-130° and at202°-204°.

EXAMPLE 6 Polymerisation

A solution of 40 mg of azobisisobutyronitrile in 5 ml of benzene isadded in the course of 5 minutes, with stirring, to a solution, heatedto 78°, of 11.4 g (0.035 mol) of1-morpholinocarbonyl-4-acryloyloxy-2,2,6,6-tetramethylpiperidine(compound No. 12) in 45 ml of benzene. The radical polymerisation issubsequently continued at 78° for 7 hours. After about 35 ml of benzenehave been distilled off in vacuo, the polymer concentrate is slowlypoured at room temperature, with vigorous stirring, into 200 ml ofdiethyl ether, as a result of which the polymer precipitates as whitepowder. The precipitate is filtered off, carefully washed with diethylether, and dried at 60° in vacuo. The colourless pulverulentpoly-1-morpholinocarbonyl-4-acryloyloxy-2,2,6,6-tetramethylpiperidinethus obtained has a softening point (T_(s)) of 185°-190° and a meanmolecular weight (M_(n)) of 3400 (compound No. 21).

There is obtained in an analogous manner, by polymerisation of thecompound No. 13:poly-1-piperidinocarbonyl-4-acryloyloxy-2,2,6,6-tetramethylpiperidine(compound No. 22), which softens at 160° and has an M_(n) of 3200.

EXAMPLE 7 Stabilisation of polypropylene sheets

100 parts of polypropylene powder (Moplen, fibre grade, from Montedison)are homogenised with 0.2 part of octadecylβ-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate and 0.25 part of alight stabiliser from the following Table 2 at 200° for 10 minutes in aBrabender plastograph. The mixture thus obtained is removed as rapidlyas possible from the kneader, and is then pressed in a toggle press togive a sheet 2-3 mm in thickness. A part of the pressed sheet obtainedis cut out and subsequently compressed between two high-gloss hardaluminium sheets in a hydraulic laboratory press for 6 minutes at 260°,under a pressure of of 12 tons, to obtain a 0.1 mm thick sheet; thissheet is tempered at 150° for 1 hour, and is then immediately quenchedin cold water. Sections are stamped out from the sheet material and areexposed in a Xenotest 1200. These test specimens are taken from theexposure apparatus at regular intervals of time, and are tested in an IRspectrophotometer for their carbonyl content. The increase in thecarbonyl extinction at 5.85μ during exposure is a measure for thephoto-oxidative degradation of the polymer (cp. L Balaban et al., J.Polymer Sci, Part C, 22, 1059-1071 (1969)), and, as experience shows, isassociated with a deterioration of the mechanical properties of thepolymer. The time until a carbonyl extinction of about 0.3 is reached,at which point the sheet is brittle, is taken as a measure of theprotective action.

                  TABLE 2                                                         ______________________________________                                                      Exposure time up to a                                           Light stabiliser                                                                            carbonyl extinction of 0.3                                      ______________________________________                                        none            890 h                                                         compound No. 8                                                                               2385 h                                                         compound No. 9                                                                              >3360 h                                                         compound No. 10                                                                             >3200 h                                                         compound No. 17                                                                              6080 h                                                         compound No. 18                                                                             >5540 h                                                         compound No. 20                                                                             >3400 h                                                         compound No. 21                                                                              2170 h                                                         compound No. 22                                                                              2080 h                                                         ______________________________________                                    

EXAMPLE 8 Stabilisation of a 2-layer metal-effect lacquer

Aluminium sheets 0.5 mm in thickness are coated with analuminium-pigmented priming lacquer based on polyester/celluloseacetobutyrate/melamine resin. Onto the wet priming lacquer is thensprayed a clear lacquer of the following composition:

58.3 parts of Viacryl®VC 373 (acrylic resin, Vianova Vienna),

27.3 parts of Maprenyl®MF 590 (melamine resin, Hochst AG, Frankfurt),

1.0 part of a 1% solution of a silicone resin in xylene,

4.0 parts of Solvesso®150 (aromatic solvent mixture),

5.4 parts of xylene, and

4.0 parts of ethyl glycol acetate.

To this is added in each case 0.9 part of one of the light stabilisersgiven in Table 3. This clear lacquer has a viscosity of 21 sec/DIN cup4. It is applied in a layer thickness of 40 μm, and is stoved at 130°for 39 minutes.

The specimens are exposed to weathering in a UVCON acceleratedweatherometer (Atlas) having a cycle of 4 hours of UV irradiation at 60°and 4 hours of weathering at 50° for 2000 hours. The 20°-gloss,according to DIN 67530, is measured after 1000 hours and after 2000hours. In addition, the specimens are examined at regular intervals oftime, under a stereomicroscope, to determine whether or not crackformation has occurred. The results are summarised in Table 3.

                  TABLE 3                                                         ______________________________________                                                                  Crack                                                          20°-Gloss after                                                                       formation                                           Light stabiliser                                                                           0 h    1000 h    2000 h                                                                              perceptible                               ______________________________________                                        none         97     47         9    after 1600 h                              compound No. 7                                                                             92     75        54    none                                      compound No. 8                                                                             96     64        36    none                                      compound No. 17                                                                            94     78        63    none                                      compound No. 18                                                                            89     59        57    none                                      ______________________________________                                    

What is claimed is:
 1. A process for the preparation of compounds of theformula II ##STR36## wherein m is an integer from 1 to 4; R is hydrogenor C₁ -C₄ alkyl; R₁ is hydrogen, C₂ -C₁₂ alkoxy, C₂ -C₂₀ alkanoyloxy,benzoyloxy, C₃ -C₂₅ carbamoyloxy or CN; R² is C₁ -C₁₈ -alkyl, C₃ -C₁₂-alkoxyalkyl, C₂ -C₈ -hydroxyalkyl, C₃ -C₁₂ -alkenyl, C₇ -C₁₄ -aralkyl,C₆ -C₁₄ aryl, C₇ -C₁₄ -alkaryl, C₃ -C₇ -cycloalkyl or2,2,6,6-tetramethylpiperidin-4-yl; R³ has one of the meanings of R² orR² and R³, together with the N atom to which they are bonded, form apiperidine, pyrrolidine, morpholine, piperidine or 4-alkylpiperidinering; and R⁴ is hydrogen or an m-valent organic radical, or R¹ and R⁴together are oxo-oxygen or a divalent organic radical; by reacting acompound of the formula IIa ##STR37## with phosgene in an inert solventin the presence of a molar amount of a base, and subsequently reactingthe product with a secondary amine of the formula R² --NH--R³, also inthe presence of a molar amount of a base.
 2. A process according toclaim 1, wherein 0.9-1.2 mols of phosgene, at least one mol of thesecondary amine and at least 2 mols of a base are used per mol of IIA.3. A process according to claim 1, wherein a tertiary amine is used asthe base.
 4. A process according to claim 1, wherein the entire reactionis carried out at temperatures below 40° C.
 5. A process according toclaim 1 in which R is hydrogen.
 6. A process according to claim 1 inwhich R¹ is hydrogen.